Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 3: Focus Session: Electron-phonon interaction and ultrafast processes in semiconductors

HL 3.8: Topical Talk

Montag, 11. März 2013, 13:15–13:45, H13

Spin lifetime and electron-phonon interaction in graphene — •Guido Burkard — University of Konstanz, Germany

Graphene and carbon nanotubes represent interesting platforms for exploring the quantum coherence of localized electron spins in suitably tailored nanostructures [1]. Due to the low density of nuclear spins in graphene, one can expect long spin coherence times. However, as in semiconductor quantum dots, the spin lifetime in graphene quantum dots at low temperatures will be limited by the spin-orbit coupling and phonon emission processes. We present a theoretical study of the spin lifetime of single electrons as a function of the magnetic field in quantum dots formed by electrostatic confinement in gapped graphene [2] and in armchair graphene nanoribbons [3]. We show that spin relaxation processes can be suppressed in a phonon cavity such as in suspended carbon nanotubes, and instead a coherent strong coupling of a single spin and a single phonon mode becomes possible [4]. This coupling opens new possibilities for spin readout [5] and manipulation.

[1] B. Trauzettel, D. V. Bulaev, D. Loss, G. Burkard, Nature Phys. 3, 192 (2007). [2] P. R. Struck, G. Burkard, Phys. Rev. B 82, 125401 (2010). [3] M. Droth, G. Burkard, Phys. Rev. B 84, 155404 (2011). [4] A. Pályi, P. R. Struck, M. Rudner, K. Flensberg, G. Burkard, Phys. Rev. Lett. 108, 206811 (2012). [5] P. R. Struck, H. Wang, G. Burkard, arXiv:1212.1569 (2012).